There are two principal disadvantages encountered when using the seals and applicators of the present state of the art:
Firstly, it is difficult to close the seals using mechanical applicators, due to the fact that there is normally only one pivot or fold point of the "loop" of the padlock, and the locking tip of the "loop" must enter the locking capsule in the body of the "padlock" in a substantially linear manner. The shape of the seals known in the state of the art is not very well adapted to operate in this way and there is a tendency, upon application of the seal, for it not to close properly. In addition to this, the marking operation becomes slow; and
Secondly, it is normally a needle portion of an applicator that penetrates the material to be marked, drawing the tip of the "loop" with it. This means that the applicator imposes design requirements which are difficult to comply with when aiming for simplicity of operation. As a result of this, mechanical applicators, as a rule, are not practical. In the majority of cases they can only be used for application of a single seal, not being provided with means for carrying a number of seals, so that multiple application of the seals at an accelerated rate can not be carried out.
Padlock seals for other purposes are known, such as that shown in U.S. Pat. No. 3,712,655 which discloses a security, tamper-proof having the general appearance of a conventional padlock. The loop or hasp of the padlock is flexible and generally hoop shaped terminating in a free end in the form of a snub nosed locking tip designed for being manually guided into a locking cavity in the body or base of the seal. Behind the locking tip of the hasp there is a protuberance or enlargement for manual gripping at the time of inserting the tip in the locking cavity.
Applicator devices are also known for the type of tie seal that is used for fixing price is tags to garments or the like. An example is to be found in FR-A-2 540 069 which discloses a pistol having jaws into which a loading mechanism inserts the locking tip at one end of the tie into an outer end of one of the jaws and the locking cavity at the other end of the tieinto an outer end of the other jaw. Rotation of the jaws about a fulcrum by means of a trigger mechanism forces the locking tip linearly into the locking cavity, a price tag or the like and a part of the garment to which it is to be fixed being interposed between the jaws.